The primary concern of radon exposure is the risk of developing lung cancer. Radon is the number one cause of lung cancer among non-smokers and the second leading cause of lung cancer among smokers (after tobacco). Luckily, this risk can be minimized through awareness and testing.
Radon is an unstable atom and breaks down into a family of elements (radon decay products). When you breathe, you will inhale both radon and radon decay products. While the radon atoms are exhaled, the radon decay products stick to the lung tissue. Radon decay products can further break down, irradiating the lung tissue and causing cell damage.
When radon and radon decay products break down, alpha particles are released. The alpha particles from the decay products are of concern because they can be released while the decay products are in the lungs. Cells in the lung do not have a thick protective coating, making them susceptible to damage from alpha particles.
When an alpha particles hits a lung cell, the cell may either die or suffer DNA damage. The cancer-suppressant gene can be impacted and cause the cell to lose its defense against cancer. This defect can be passed on to new cells, increasing the potential for lung cancer.